Material of the formula Y.sub.2 BaCuO.sub.5, also referred to as the 2-1-1 phase, is known to furnish flux pinning centers in the well known 1-2-3 yttrium--barium--copper superconductor material. See, e.g., an article by A. K. Gangopadhyay et al. entitled "Flux pinning and irreversibility temperature in . . . superconductors" Physica C, Vol. 201, P6-P12 (1992). Thus, a 1-2-3 superconductor comprised of a 2-1-1 material dispersed therein will have a higher critical current than a comparable 1-2-3 superconductor without such 2-1-1 material therein.
Not every 2-1-1 material has the desired effect upon the 1-2-3 superconductor, however. Unless the particle size of the 2-1-1 material is less than about 100 nanometers (and preferably from about 10 to about 100 nanometers), the critical current of the 1-2-3 superconductor will not be substantially affected.
Applicant is not aware of any prior art process which enables one to make the 2-1-1 material with a particle size of less than 100 nanometers and which is suitable for large scale production, which produces the 2-1-1 material in relatively high yields, which is relatively inexpensive, and which produces substantially uniform particles sizes.
It is an object of this invention to provide a process for making a 2-1-1 material with a particle size of less than 100 nanometers which is suitable for large scale production, which produces the 2-1-1 material in relatively high yields, which is relatively inexpensive, and which produces substantially uniform particle sizes.